Department of Cell Biology and Imaging, Faculty of Biology and Earth Sciences, Jagiellonian University, 30-387, Krakow, Poland.
Department of Medical Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387, Krakow, Poland.
Mol Neurobiol. 2017 Sep;54(7):4953-4962. doi: 10.1007/s12035-016-0026-9. Epub 2016 Aug 13.
The Drosophila retina has an autonomous peripheral circadian clock in which the expression of the gene encoding heme oxygenase (HO) is under circadian control with the ho mRNA peaking at the beginning of the day and in the middle of the night. The function of HO in the retina is unknown, but we observed that it regulates the circadian clock and protects photoreceptors against DNA damage. The decline in HO level increases and decreases the expression of the canonical clock genes period (per) and Clock (Clk), respectively. The opposite result was observed after increasing HO expression. Among three products of HO activity-carbon monoxide (CO), ferrous ions, and biliverdin-the latter has no effect on per and Clk expressions, but CO exerts the same effect as the increase of ho expression. This suggests that HO action on the clock is mediated by CO, which may affect Clk expression during the day and the level of per expression. While ho expression is not stimulated by nitric oxide (NO), NO has the same effect on the clock as HO, increasing Clk expression and decreasing the expression of per.
果蝇的视网膜中存在一个自主的外周生物钟，其中编码血红素加氧酶（HO）的基因表达受到昼夜节律的控制，HO mRNA 在白天和午夜达到峰值。HO 在视网膜中的功能尚不清楚，但我们观察到它可以调节生物钟并保护光感受器免受 DNA 损伤。HO 水平的下降分别增加和减少了经典生物钟基因周期（per）和时钟（Clk）的表达。增加 HO 表达后则观察到相反的结果。HO 活性的三种产物——一氧化碳（CO）、亚铁离子和胆绿素——后者对 per 和 Clk 的表达没有影响，但 CO 发挥与增加 ho 表达相同的作用。这表明 HO 对生物钟的作用是由 CO 介导的，CO 可能会影响白天 Clk 的表达和 per 表达水平。虽然 NO 不会刺激 ho 的表达，但 NO 对生物钟的作用与 HO 相同，增加了 Clk 的表达并降低了 per 的表达。
